1. Field of the Invention
The present invention relates to a magnetic head assembly for a flexible magnetic disk drive unit. More particularly, it relates to a magnetic head assembly having a magnetic recording and retrieving head or heads brought into contact with a flexible magnetic recording disk consisting of a metallic thin-film type magnetic recording medium for carrying out magnetic recording on and retrieving information from the flexible magnetic disk.
2. Description of the Related Art
A flexible magnetic disk drive unit employing a flexible magnetic recording medium, such as a floppy disk unit or a micro-disk unit used as a secondary information storage unit for an electronic computer, is well known.
Recently, the demand for high density recording on the flexible magnetic recording medium has increased. To meet this demand, instead of the conventional flexible magnetic medium having a magnetic recording layer coated on the surface of a flexible nonmagnetic base by the use of a conventional binder, there has been proposed a metallic thin-film type flexible magnetic recording medium using, as a magnetic recording layer, a strongly magnetic metallic thin-film or a metallic thin-film formed by a sputtering method, such as a cobalt system alloy film having a perpendicular magnetic anisotropy as disclosed in Japanese Examined Patent Publication No. 58-91 (corresponding to U.S. Pat. No. 4,210,946), or Japanese Unexamined Patent Publication No. 61-5404. However, when employing the metallic thin-film as a magnetic recording layer of the flexible magnetic recording medium, a problem arises in that, as a conventional magnetic head assembly having a magnetic read/write head, a magnetic erase head and pressure pads must be subjected to a large frictional resistance when in contact with the metallic thin-film, the magnetic heads as well as the magnetic recording medium are worn and damaged by this friction. As a result, both the magnetic heads and the medium are not sufficiently durable and do not have a long operational life. Particularly, when the conventional flexible magnetic disk drive unit is employed for a magnetic recording on both sides of the flexible magnetic recording medium having the above-mentioned metallic thin-film recording layers on both surfaces thereof, the problem of a sufficient durability, and an additional problem of stability in contact between the magnetic head assembly and both sides of the flexible magnetic recording medium, become more critical and stringent. As a result, the conventional flexible magnetic disk drive unit cannot be practically applied as a double-sided magnetic flexible disk drive unit for the metallic thin-film type magnetic flexible recording medium. Therefore, provision of a practically applicable magnetic head assembly capable of being accommodated in the flexible magnetic disk drive unit for a metallic thin-film type magnetic recording medium is demanded.
When the above-mentioned metallic thin-film having a perpendicular magnetic anisotropy is used for forming a magnetic recording layer or layers of a flexible magnetic recording medium or disk, a magnetic read/write head per se must have sufficient durability to ensure a long operational life, and must be highly sensitive during perpendicular magnetic recording and retrieving. Also, a magnetic flexible disk cartridge containing the above-mentioned metallic thin-film type magnetic recording medium therein must be held in a casing in such a manner that stable magnetic recording and retrieving operations can be carried out over a long operational life.